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MathGroup Archive 2005

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Re: calculate de Jong function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg56982] Re: [mg56969] calculate de Jong function
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 12 May 2005 02:32:15 -0400 (EDT)
  • Reply-to: hanlonr at cox.net
  • Sender: owner-wri-mathgroup at wolfram.com

x={x1,x2,x3,x4};

Use Dot

f1[x_?VectorQ] := x.x;

f1[x]

x1^2 + x2^2 + x3^2 + x4^2

or

f2[x_?VectorQ] := Tr[x^2];

f2[x]

x1^2 + x2^2 + x3^2 + x4^2

or

f3[x_?VectorQ] := Plus@@(x^2);

f3[x]

x1^2 + x2^2 + x3^2 + x4^2

or

f4[x_?VectorQ] := Inner[Times,x,x];

f4[x]

x1^2 + x2^2 + x3^2 + x4^2


Bob Hanlon

> 
> From: Stefan Schuster <bi1169*delete_from_star_to_star*@fh-
To: mathgroup at smc.vnet.net
> Date: 2005/05/11 Wed AM 05:24:54 EDT
> To: mathgroup at smc.vnet.net
> Subject: [mg56982] [mg56969] calculate de Jong function
> 
> Hello,
> 
> I don't know how I should implement the first de jong function:
> 
> f(x)=Sum((x_i)^2)
> where x is a Vector with n dimensions and x_i is the value of the i-th 
> Dimension.
> i.e. all Values of the Vector are squared and added.
> 
> My problem is that I don't know how many Dimensions there are, so I 
> can't define the borders of the SUM function.
> 
> thanks in advance for help
> 
> Stefan
> 
> 


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